1. Field:
The present disclosure relates generally to aircraft and, in particular, to control surfaces for aircraft. Still more particularly, the present disclosure relates to a method and apparatus for a leading edge device on a wing of an aircraft.
2. Background:
The wings of an aircraft are designed to generate lift as the aircraft moves. The configuration of a wing during flight at a cruising altitude may provide less lift at slower speeds when the aircraft is landing as control surfaces are used to change the configuration of an aircraft to provide lift augmentation.
Leading edge devices are commonly used to provide this additional lift. Leading edge devices are extensions of the front of a wing. These devices are used to reduce a stalling speed by altering the airflow over the wing.
An example of a leading edge device is a slat. Slats may be fixed or moveable. A retractable slat, as commonly used in commercial aircraft, provides for a reduced stalling speed at takeoff and landing. These slats are retracted for cruising to provide increased performance. An example of other control surfaces that are used to increase lift during takeoffs and landings are trailing devices, such as flaps.
Although these devices provide for increased lift during takeoff and landing, these types of devices may generate noise. Noise from aircraft is a public issue with respect to quality of life. Noise generated by aircraft during landings and takeoffs have impacts on areas around and nearby airports. With these concerns and legislative controls, aircraft manufacturers and operators have developed and implemented quieter aircraft and better operating procedures.
Aircraft manufacturers have focused on many different aspects of noise generated by an aircraft. For example, manufacturers have developed high-bypass turbo fan engines, which are quieter than the turbo jet engines and low-bypass turbo fans in previous aircraft models. Additionally, manufacturers have focused on other noise generation sources in an aircraft. One source of noise is the deployment of leading edge devices and trailing devices, such as flaps and slats.
When a leading edge device, such as a slat, is extended to increase lift, the amount of noise generated by the aircraft may increase. This increase in noise may be generated by air passing over the slat and the gap between the slat and the wing.
One currently available solution involves using a leading edge flap, which provides reduced noise as compared to a slat that extends. This device, however, may reduce the amount of lift that can be generated as compared to using extendable slats.
Therefore, it would be advantageous to have a method and apparatus that takes into account one or more of the issues discussed above.